Understanding Ransomware: How It Works and How to Defend Against It

Ransomware has become one of the most significant cybersecurity threats facing businesses today. The ability of attackers to encrypt critical data, hold it hostage, and demand ransom payments has crippled companies of all sizes. Earlier this year, a ransomware attack on Synnovis, a provider of lab services to the NHS, resulted in cancelled appointments and data released on the darknet. Qilin, a Russian cybercriminal group, shared almost 400GB of private information including patient names, dates of birth, NHS numbers and descriptions of blood tests, when their Bitcoin ransom demand was, supposedly, not paid.

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While attacks on large corporations and public institutions make the headlines, small and midsize businesses are just as vulnerable, if not more so. In fact, 82% of all ransomware attacks target SMBs, although many business leaders have an “it’ll never happen to me” mindset. And, according to data from Palo Alto Networks’ threat intelligence arm, Unit 42, manufacturers are a prime target for ransomware, accounting for 17.2% of attacks in 2023, with professional and legal service firms following close behind.

For IT leaders across all industries and scales, ransomware presents a challenge that requires a comprehensive strategy to defend against, mitigate, and recover from these attacks.

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In this article, we’ll break down how ransomware works, the typical tactics attackers use, and the network security solutions, such as next-generation firewalls (NGFWs), that can help protect your business from this growing threat.

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What is Ransomware?

Ransomware is a type of malicious software designed to block access to a computer system or data until a ransom is paid. Attackers use a variety of methods to infect systems, including phishing emails, malicious websites, or exploiting software vulnerabilities. Once inside, the ransomware encrypts files, rendering them unusable until the victim pays a ransom, typically in cryptocurrency.

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There are two main types of ransomware:

1. Locker Ransomware: Blocks basic computer functions, locking users out of their devices until payment is made.
2. Crypto Ransomware: Encrypts individual files and folders, making them inaccessible to users.

In either case, attackers often create a sense of urgency by threatening to delete data, publish it on the darknet, or raise the ransom if it’s not paid by a deadline.

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How Ransomware Infiltrates Your Network

Ransomware attacks usually start with one of the following methods:

• Phishing Emails: Attackers trick employees into clicking on malicious links or downloading infected attachments, allowing ransomware to spread across the network.
• Exploit Kits: Cybercriminals use vulnerabilities in outdated software, unpatched systems, or web applications to install ransomware without user interaction.
• Remote Desktop Protocol (RDP): Weak RDP credentials allow attackers to gain unauthorised access to systems, often using brute force to guess passwords and install ransomware.

Once inside, ransomware can quickly propagate across networks, encrypting files on local drives, cloud storage, and connected devices. This is why a layered defence strategy is essential to protecting your network and preventing widespread damage.

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The Role of Next-Generation Firewalls in Ransomware Defence

While no single solution can fully protect your network from ransomware, Next-Generation Firewalls (NGFWs) play a critical role as part of a layered security strategy. NGFWs provide advanced threat detection and prevention features, adding an essential layer of defence by monitoring traffic and stopping threats before they reach your systems.

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Traditional firewalls often struggle to detect sophisticated ransomware attacks, as they focus on packet filtering based on static rules. In contrast, Next-Generation Firewalls (NGFWs) are designed to address modern threats like ransomware by providing deeper visibility into network traffic and offering advanced threat prevention features.

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Here’s how NGFWs can help protect your network from ransomware:

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1. Deep Packet Inspection (DPI)

NGFWs use DPI to analyse the contents of data packets rather than just looking at headers. This allows the firewall to detect and block malicious payloads, including ransomware, before they reach the endpoint. This inspection extends to encrypted traffic, which is a key method ransomware uses to evade detection.

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2. Intrusion Prevention Systems (IPS)

An NGFW includes built-in IPS capabilities that monitor network traffic for suspicious behaviour. IPS can detect and block known vulnerabilities that ransomware exploits, as well as flag abnormal patterns indicative of a ransomware infection.

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3. Sandboxing

Many NGFWs offer sandboxing technology, which isolates and executes suspicious files in a secure environment. This prevents potentially harmful code from running on your network while allowing the firewall to identify if a file is ransomware.

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4. URL Filtering and Phishing Protection

NGFWs can filter out malicious websites and block phishing attempts that deliver ransomware. By analysing the reputation and content of URLs, NGFWs help prevent employees from accidentally downloading ransomware through harmful links.

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5. Zero-Day Threat Detection

NGFWs are equipped to handle zero-day ransomware attacks — threats that exploit previously unknown vulnerabilities. By leveraging threat intelligence and machine learning, NGFWs can detect and block suspicious behaviour that could indicate a ransomware attempt, even if the specific strain is new.

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Learn more about NGFWs here. [hyperlink to landing page]

How to Defend Against Ransomware Attacks

While NGFWs play a critical role in defending against ransomware, a comprehensive approach to security is necessary. Here are the key strategies IT leaders should implement:

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1. Regular Patch Management

Keeping software up-to-date is crucial. Many ransomware attacks exploit known vulnerabilities in operating systems, applications, and devices. Ensure patch management is automated, so critical updates are applied as soon as they’re released.

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2. Backup and Disaster Recovery

Regular backups can save your business from the worst consequences of a ransomware attack. Ensure that backups are frequent, encrypted, and stored offline, so they cannot be accessed or encrypted by attackers. Periodically test your backup and disaster recovery processes to ensure they work effectively.

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3. Employee Training

Most ransomware infections begin with human error, particularly from phishing attacks. Conduct regular cybersecurity training for all employees, focusing on how to spot phishing emails, avoid suspicious downloads, and report potential threats.

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4. Multi-Factor Authentication (MFA)

Enable MFA for all remote access to your systems, including VPNs and RDP sessions. This adds an extra layer of security to prevent unauthorised access, even if login credentials are stolen.

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5. Endpoint Detection and Response (EDR)

Deploy EDR solutions that can monitor and respond to suspicious activity on endpoints. EDR tools can detect ransomware activity at the endpoint level, quarantining affected systems before the malware spreads.

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6. Network Segmentation

By dividing your network into isolated segments, you can prevent ransomware from spreading across the entire organisation. If one section of the network is compromised, segmentation helps contain the infection, limiting the damage.

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Ransomware is an evolving threat, but with the right network security solutions and proactive strategies, your business can stay ahead of attackers.

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Is your business ready to defend against ransomware? 

Contact us today to learn how security solutions, including NGFWs, can strengthen your security posture.

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